Ответы и объяснения

2013-03-19T17:45:52+04:00

tg (a +b ) = (tg a + tg b )/ (1 - tg a * tg b )

tg (a +b ) =  1/3 +2/3 / 1 - 1/3*2/3 = 1 / 1- 2/3= 1/ 1/3= 3

2013-03-19T17:47:25+04:00